How a Swimming Pool Can Cool a Power Plant

Inspired by the enormous swimming pools he builds as part of his real estate business, Chilean biochemist Fernando Fischmann and his company, Crystal Lagoons Corp., have devised a new design for a power plant cooling system. It recycles and cleans the water rather than dumping it out to sea and endangering wildlife.

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Fernando Fischmann is a Chilean biochemist turned real estate mogul. And, if his new idea works out, he could make another career turn—inventor of a way to make power plants more ocean-friendly. Inspired by the giant pools he's built for resorts, Fischmann came up with the idea of using closed pools to provide the water to cool large power plants, reducing their environmental impact.

It all started with Fischmann's filtration system. Any pool owner knows the pain of keeping one clean, but Fischmann was working on a different scale. The largest pool made by his company, Crystal Lagoons, was built for the San Alfonso del Mar resort in Chile: It contains enough water to fill 6000 ordinary swimming pools, Fischmann says. Cleaning it the way you would your backyard pool would require 6000 standard filters and another 6000 doses of chlorine. Fischmann put his biochemistry skills to work figuring out a more practical solution.

The resultant water treatment system, which took six years to develop, is composed of only two steps. "You need permanent application of chemicals and then a filtration system," says Fischmann. The Crystal Lagoons technology doesn't add a constant flow of chemicals to the water. Instead, 400 sensors per acre continually monitor bacteria and algae levels. When those levels get too high, the system automatically injects the same chemicals used to treat drinking water, such as chlorine (to disinfect the water) and lime (to keep the pH level balanced). Because these chemicals are applied more efficiently, the amount that the pools need is 100 times less than what's used in an equivalent drinking water system. Ultrasonic pulses then cause algae to cluster up, making the filtration stage easier and more efficient.

It worked so well in a massive swimming pool that Fischmann realized his technology could be applied to other large bodies of water. "The possibility of treating huge amounts of water is something important to many other industries," he says. "One of the industries we thought of as a good possibility was cooling [power] plants."

All thermoelectric plants—those that generate electricity with steam, whether they use nuclear or fossil fuels to create it—need a constant supply of water to the system's condenser to cool down the exhaust. Every megawatt-hour of electricity produced requires an average of 40,000 gallons of water, according to a 2009 study by the U.S. Government Accountability Office. As a result, large plants are usually built close to bodies of water, such as rivers or oceans, and their cooling water (which is quite warm by the time it's released) often pours back into the environment.

Michael Kennish, a research professor at Rutgers' Institute of Marine and Coastal Sciences, points out how cooling water from this once-through system can damage the ecosystem: Fish are either drawn nearer to the plant or forced out to sea; either way they are forced into harsh conditions outside of their natural habitat and killed. This effect is so detrimental that the state of California banned the once-through method for cooling thermoelectric plants, and the EPA prohibits the construction of any new systems. Currently, many U.S. power plants use a wet-recirculation system, where wastewater originally taken from a body of water is not released back into the environment immediately, but pumped to cooling towers and then reused. The Union of Concerned Scientists (UCS), an environmental science advocacy groupm says that these systems are predominant in the Western U.S. Dry cooling, where only air is used to cool the plant, is commonly used in smaller plants.

Fischmann says his company's giant pools and advanced filtration system offer a different way to cool power plants: He could create a closed system that recycles the same water supply—essentially replacing the ocean with a huge swimming pool. Instead of drawing water from an ocean or river, a power plant using Fischmann's system would pump water from the pool to the plant's condenser. Because warm plant wastewater is perfect for algae and other microorganism growth, the system would use Fischmann's filtration setup to filter any contaminants as it releases the water back into the pool to be used again. "It's a closed system that is separated from the environment so that you don't produce any kind of environmental damage," he says.

However, closed systems bring trade-offs, according to John Rogers, senior energy analyst at the UCS. For example, though Fischmann's is a closed system, it isn't fully self-sufficient, he says—it would need to compensate for the water lost to evaporation. And cooling a 100-megawatt plant with the Fischmann system requires a 22-acre pool of water, so the system consumes a lot of water.

Despite these challenges, Fischmann argues that his system can do what other cooling systems can't. Besides their danger to the environment, once-through systems need to be near large bodies of water, while the cooling pools could allow water-cooled power plants to be built far inland, away from any major bodies of water. Dry cooling systems, though they don't have water demands, are relatively inefficient therefore increase the cost of electricity, according to the UCS. Fischmann's pools are more efficient than dry cooling systems, and the water they need to keep up with evaporation losses is less than what's required to keep wet recirculation systems fully stocked. (Because wet recirculation systems aren't filtered, operators have to extract some of the water and replace it with fresh water to keep too much contamination from building up.)

Fischmann won't give away too many details of his system's specs, as he's currently in talks with major power plant companies to build such pools in the news few years. But one of his favorite tidbits, being a real estate mogul, is that the cooling pools would clean water so thoroughly that they would actually be safe to use as a swimming pools. And because the system captures much of the plant's heat rather than pumping it out to sea, that energy could be corralled to keep the pool at a pleasant 68 degrees F. It remains to be seen, however, whether people are game to swim laps in a power plant's cooling system.